Reminders of Halley’s Comet

The Eta Aquarid meteor shower returns

By J. Alex Knoll

The moon wanes through morning skies this week, reaching last quarter Thursday, May 2, when it shines between the faint constellations Capricornus and Aquarius and is high in the south by dawn.
The sun sets this week around 8pm, revealing Jupiter high in the west, brighter than any star. However, if you have a clear view of the west-northwest horizon just after sunset, you may find the only brighter star-like object to the lower right of Jupiter: Venus, which is slowly pulling away from the glare of the setting sun. You may need to scour the horizon line with binoculars in the 20 minutes following sunset to spot Venus this week. But each night it appears a little higher at sunset and sets a little later. Jupiter sets before 11pm, by which time Saturn should be well positioned in the southeast. Less than a week past opposition, the ringed planet is visible throughout the night.
While we won’t have another visit from Halley’s Comet until 2061, we are reminded of it each year at this time as the earth passes through a trail of debris left in its wake, resulting in the Eta Aquarid meteor shower. This year’s shower peaks in the wee hours before sunrise Sunday, May 5, with perhaps 10 meteors an hour.
As the bits of comet flotsam collide with Earth’s atmosphere, they burst aflame and streak across our sky at upward of 150,000 miles an hour, often leaving persistent trains of light visible for several seconds. These trains are a testament of the massive energy released at impact, which strips electrons from the meteors’ atoms, converting them into a trail of ionized gas or plasma, the fourth state of matter. You can spot an Eta Aquarid meteor anywhere overhead — and for several days before and after peak. But they all appear to originate from the constellation Aquarius, which rises after midnight, and its star Eta Aquarii.